Unit for crushing and distributing powdered stone in coal mines



n 7 1927. 8 s. TESCHER UNIT FOR CRUSHING AND DISTRIBUTING PQWDERED STONE IN COAL MINES 2 Sheets-Sheet 1 Filed Nov. 20. 1924 Jung .7, 1927.

r s. TESCHER UNIT FOR CRUSHING AND DISTRIBUTING POWDERED STONE IN GOAL MINES Filed Nov. 20. 1924 2 Sheets-Sheet 2 I gnucwfol, Samue/ Tesc/zer Patented June .7, 1927.

UNITED STATES PATENT OFFICE.

SAMUEL TESCHER, OF DENVER, COLORADO.

UNIT FOR GRUSHING AND DISTRIBUTING POVDERED STONE IN COAL MINES.

Application filed November 20, 1924.

This invention relates to machines for distributing crushed rock and similarmaterial in the form of dust to the exposed surfaces of a mine for the purpose 01 covering the dangerous coal dust in the mine with rock dust so as to render the coal dust harmless,

' experimental and practical tests made by the United States Bureau of Mines having demonstrated that very fine rock dust placed on the underground surfaces of coal mines is very eflicacious inlimiting and preventing coal mine explosions.

In common and ordinary practice the rock material is crushed very finely on the surface. It is then sacked and transported into the mine for distribution and then is blown by blowers onto the rock faces and.

the waste of the fines in transportation,

but it will be understood, of course, that the finer this rock dust is. the better and the more thoroughly it may be blown through the mine and distributed upon the rock and timber faces. r

The object of this invention is to reduce the expense of covering the rock faces with the rock dust as required and dothisby eliminating the expense of crushing the rock material on the surface, sacking it, and then transporting it into the mine tormechanical distribution, and in this connection to provide a unitary motor, crusher and tan mounted upon one bed plate and truck so that the entire unit can be transported from place to place within the coal mine workings, thus permitting the machine to be moved into nearly all parts of the mine so that every crook, creviceand lodging place for the dangerous coal dust'can be thoroughly covered with the rock dust soas to render the coal dust entirely harmless.

A further object is to provide a machine of this character which is so designed that.

only the very fine material is exhausted from the crusher and blown into the mine all currents, giving a. smoke screen of very fine Serial No. 751,132.

move this machine with its wires into the return airways the machine can be kept on the intake airways and pipe extensions placed from the exhaust through stoppings or doors in such a manner as to reach all the workings on, the returnairways.

Other objects will appear in the course of the following description.

My invention is illustrated in the accompanying drawings, wherein Figure 1 is a top plan view of a combined crushing and distributing'unit constructed in accordance with my invention;

Figure 2 is a side elevation of the con struction shown in Figure 1;

Figure 3 is an end elevation Figure 4 is a transverse sectional view through the stone crusher.

Referring to these drawings, 10 designates a truck which has the form of a. standard mine car truck and provided with the wheels 11 and the bed plate 12, the beams of the truck being connected by cross braces 13. Mounted upon this bed plate is an electric motor 14.- of any usual construction and having the usual shaft 15. Mounted upon the bed plate 12 is a stone crusher, designated generally 16. The casing has an opening in its top closed by a lid 17 whereby the stone may be fed into the crusher. The crusher is operated by power transmitted from the motor 14 to a flexible coupling 18 which is engaged with a crusher shaft 15. Mounted in connection with the crusher is an exhaust fan .19 carried upon the extremity of the shaft '15. which exhaust tanand its casingmay be of any suitable construction.

The fan casing 20 is connected by a pipe 21 to the stone crusher, this pipe entering at the center of the fan casing. Disposed within the fan casing is the usual exhaust tan having approximately radial blades and discharging tangentially through a tangential pipe 22. This pipe 22 may extend any desired length and he formed of sections flexibly connected to each other or of flexible pipe A perforated screen 23 is disposed within the crusher at the lower end thereof and the fan exhausting from the top of the crusher hopper draws air through this screen and hopper, picking up only the very fine materials from the crusher. The screen acts to admit air but prevents passage from the crusher of such particles as would otherwise fall by gravity therefrom. At the same time,

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this screen tends to divide the air passing through the crusher to prevent application thereof to the dust Within the crusher at any one particular point in sufficient force to cause exhausting from the crusher of such particles as might not have been properly divided.

The crusher, as shown in Figure 4c, is of a standard type and includes a rotatable element 24 mounted upon the shaft 15 and carrying upon it the hammers These hammers operate over a concave 2.6 having perforations through which the broken rock passes. The shaft 15 extends through the casing 16 and 'nto the casing 19 of the lolovver and the fan blades of the blower are mounted upon this shaft. One distinction between the crusher :as illustrated and the crusher as ordinarily used is that the fine dust is taken out through the pipe 21 hy the exhaustfan. If there was no exhaust fan th crushed rock would pass out through the perforations in the concave.

It is standard practice to connect the motor to a crushing device of this kind by means of a flexible coupling. The motor shaft extends only so far as this coupling, While the crusher shaft extends clear through the crusher sufficiently far to accommodate the centrifugal fan. As before remarked, the blower may he of any suitable character. Preferably the crusher and the fan are driven by electricity, but I do not wish to be limited to the use of an electric motor as other motors might be used.

It will be obvious that the machine is particularly mobile and can be moved into nearly all parts of the mine so that every rook, crevice and lodging place can be thoroughly covered with rock dust. Coarse rock material of shale or other non-sili-cious material is fed into the crusher through the hinged lid opening on the top. his mate rial is ground up or pulverized in the crusher and the very fine powder resulting is simultaneously Withdrawn from the hopper on top of the crusher through a pipe of large cross sectional area 21 into the fan and then is blown out from the fan into the air currents.

By the use of this machine. the expense of initially crushing; the rock material on the surface. sacking it. and then transportinn this material into the mine for mechani cal distribution is avoided. Where the rock material is crushed on the surface and transported into the mine, a very large percentage of the very finely pulverized dust is lost, and tests have shown that this very fine material is the most efficient in actual use. By blowing this finely crushed or pulverized rock material into the mine and particularly close to the place Where it is desired to cover the surface, the dust is deposited in the same manner in Which the dangerous coal dust- Was originally deposited, that is by the travel of the currents, that the lodging places for the coal dust will also lodging places for the rock dust.

It will be obvious, of course,tl1at the inachine will he made in sizes to suit the tract. gauge and clearance dimensions of any particular mine and may he varied to suit various conditions by the use of difierent sizes and capacities 0 machine, that is the track gauge can be varied, the size of the motor, the crusher, or the fan. can also be varied to suit conditions which most advantageous for any particular case. By the use of this machine within a coal mine, the rock dust has no opportunity for "(taking as it does where the material is crushed on the surface and then carried into the mine, hut the rock dust is kept in suspension throughout the entire operation from the time it is freshly crushed until the time it lodged on the rock faces. v

In tests covering a period of ninety days, it has been demonstrated that with this machine all rock surfaces can be reached and actual dust clouds have been seen coming from the mine fans which were located at nine thousand feet from the point of opera tion of the machine. The depositions of dust shown by these tests have occurred on top of rnine timbers, on the reverse side mine props, in crosscuts which have been driven off of the entries in which the machine was operating, :on the roofs, and on every projection and crevice in the. mine surfaces throughouttheir entire length.

I claim:

In a stone crushing and distributing unit,

a pulverizer having :afeed hopper at its upper end, a grated opening at its lower end, means for introducing air under presssure through the grated opening and an out.-

let for finely divided material communieating with the hopper.

In testimony whereof I hereunto aiiix my signature.

SAMUEL TESCHEB. 

